Field of the Invention
The present invention relates to a wireless communication, and more particularly a method and device for providing a security communication using a polar code.
Related Art
In a data communication system, it should be ensured that data which a sender (Alice) sends is not eavesdropped by a non-intended user (Eve) and is received only by an intended user (Bob) in a secure manner. In this secure communication, conventionally, techniques based on cryptography have been employed. In such cryptography-based techniques, a secret key is used. In this connection, various approaches allow only Alice to be aware of a current secret key, and, thereafter, Alice encrypts data using the current secret key, which, in turn, is sent to Bob. Bob decodes the received data using the current secret key. Although such cryptography-based techniques have been employed by many communication systems for a long time, such cryptography-based techniques require a system for generating/distributing/maintaining the secret key. In some of such systems, a secure generating/distributing/maintaining of the secret key may be very difficult or even impossible. In order to solve this problem, recently, totally different techniques are studied vigorously to provide a communication security, among which there is a physical layer security technique. While the previous cryptography-based techniques provide a security for an upper layer of a communication system, the physical layer security technique provides a security for a physical layer of the communication system. Details about the physical layer security technique are disclosed in a following [Ref 1]:
Ref [1] R. Liu and W Trappe, Securing wireless communications at the physical layer, Springer, 2010.
Up to now, the most effective method to substantially provide the communication security based on the physical layer security concept is a polar coding scheme. A method for providing the physical layer security using the polar coding scheme is well disclosed in a following article:
Ref [2] H Mandavifar and A. Vardy, “Achieving the Secrecy Capacity of Wiretap Channels Using Polar Codes,” IEEE Transactions on Information Theory, Vol 57, Issue 10, Page(s): 6428-443, October, 2011.
Such a polar coding scheme may be referred to as a “secure polar coding scheme”. In the previous method for providing the physical layer security using the polar coding scheme, the coding method is constructed using an assumption that Alice is aware of instantaneous channel information for Bob and Eve. When there is feedback information from Bob to Alice in an actual communication environment, Alice may know the instantaneous channel information for Bob. Especially, it may frequently be case that there is not feedback information from Eve to Alice in an actual communication environment. It may be more reasonable to assume that Alice does not know the instantaneous channel information for Eve. Eventually, in the previous method, when the instantaneous channel information is not known, the secure polar coding scheme may not be available.